Key Points
Question
Does epiretinal membrane peeling result in resolution of diplopia in patients who have preoperative diplopia and/or new-onset diplopia in patients who do not?
Findings
In this cohort study, 33% of patients with central-peripheral rivalry–type diplopia before epiretinal membrane peeling had resolution of diplopia postoperatively and 19% of patients with no diplopia before epiretinal membrane peeling had new-onset central-peripheral rivalry–type diplopia postoperatively. New-onset diplopia postoperatively may be associated with better postoperative operated-eye visual acuity.
Meaning
Epiretinal membrane peeling may lead to resolution of diplopia in some patients but new-onset diplopia in others.
Abstract
Importance
The peeling of an epiretinal membrane (ERM) is commonly performed for poor visual acuity and/or metamorphopsia, but to our knowledge, its influence on central-peripheral rivalry (CPR)–type diplopia has not been rigorously studied.
Objective
To evaluate the occurrence of either resolution or new-onset CPR-type diplopia in patients undergoing ERM peeling.
Design, Setting, and Participants
This prospective cohort study was conducted from July 2014 to April 2018 at a tertiary referral medical center and included 33 adults with ERM who were undergoing peeling surgery with planned preoperative to postoperative analysis.
Interventions
A standardized diplopia questionnaire completed before undergoing and 6 months following ERM peeling.
Main Outcomes and Measures
For patients with CPR-type diplopia before ERM peeling (rated “sometimes” or more for distance straight ahead or reading using the diplopia questionnaire), we calculated the proportion with resolution of diplopia postpeel (“never” for distance straight ahead and reading on the diplopia questionnaire) and compared clinical characteristics between those with resolution and those without. For patients with no diplopia prepeeling (“never” for distance straight ahead and reading on the diplopia questionnaire), we calculated the proportion with new-onset CPR-type diplopia postoperatively and compared clinical characteristics between those with new-onset diplopia and those who remained without diplopia.
Results
Of 33 patients (median age, 67 years [range, 51-87 years]; 18 men [55%]), 12 (36%) had CPR-type diplopia preoperatively and 21 (64%) did not have diplopia preoperatively. Six months postoperatively, 4 of 12 patients with diplopia (33%; 95% CI, 10%-65%) had resolution of diplopia, and 4 of 21 patients without diplopia (19%; 95% CI, 5%-42%) had new-onset diplopia. Better postoperative operated-eye visual acuity appeared somewhat associated with new-onset diplopia postoperatively (mean [SD] visual acuity, 0.08 [0.10] logMAR; approximately 20/25 vs 0.34 [0.33] logMAR; approximately 20/40; difference, −0.27; 95% CI, −0.62 to 0.09; P = .07), as did greater postoperative aniseikonia (14% [5%] vs 6% [4%]; difference, 8%; 95% CI, 2%-13%; P = .04).
Conclusions and Relevance
These data suggest that epiretinal membrane peeling may result in resolution of diplopia in some patients but new-onset diplopia in others. These findings may be valuable when counseling patients regarding the risks of new-onset diplopia.
This cohort study examines the occurrence of resolution of diplopia vs new-onset diplopia in patients who are undergoing epiretinal membrance peeling.
Introduction
Epiretinal membranes (ERMs) may be associated with central-peripheral rivalry (CPR)–type diplopia1 (also known as macular or retinal diplopia, or dragged-fovea diplopia2). The aim of the present study was to evaluate the influence of ERM peeling on diplopia status.
Methods
Institutional review board approval was obtained from the Mayo Clinic. All procedures and data collection were conducted in a manner that complied with the Health Insurance Portability and Accountability Act. All research procedures adhered to the tenets of the Declaration of Helsinki. Verbal consent was obtained from all study participants.
Patients
Patients who received a diagnosis of ERM and were undergoing ERM peeling were prospectively and consecutively enrolled from the retina practice of a single surgeon (RI). Patients with full-thickness macular hole or rhegmatogenous retinal detachment involving the macula were excluded. Nonoperated eye visual acuity was required to be 20/40 or better.
Preoperatively, patients underwent an orthoptic evaluation and completed a diplopia questionnaire3 (http://www.pedig.net), rating diplopia as “never,” “rarely,” “sometimes,” “often,” or “always.” A reevaluation of diplopia occurred 6 months postoperatively (window, 9-156 weeks) using the diplopia questionnaire. Postoperative diplopia evaluation was performed after any cataract surgery.
Clinical Testing
As described previously,1,4 retinal misregistration may be identified using the optotype-frame test and/or synoptophore superimposition slides.1,5 It may also manifest as metamorphopsia (incomplete data; assessed using M-charts6; Inami & Co) or aniseikonia (assessed using the New Aniseikonia Test7).
Central-peripheral rivalry–type diplopia was defined as binocular diplopia with retinal misregistration in which other barriers to fusion did not fully explain diplopia. For example, care was taken to rule out monocular diplopia, potentially caused by cataracts. We required a minimum frequency of “sometimes” on the diplopia questionnaire for straight ahead or reading to classify a patient as having diplopia.
The validated Adult Strabismus-20 (AS-20) questionnaire (http://www.pedig.net) was completed preoperatively and postoperatively.8 Each of the 4 domains (self-perception, interactions, reading function, and general function), was Rasch scored and converted to 0 to 100 for interpretation.8
Analysis
Two groups of patients were analyzed: (1) CPR-type diplopia preoperatively and (2) no diplopia preoperatively. For patients with CPR-type diplopia preoperatively, resolution was defined as “never” diplopic for both straight ahead and reading. For patients with no diplopia preoperatively, new-onset CPR-type diplopia postoperatively was defined as diplopia rated “sometimes” or more straight ahead or reading with evidence of retinal misregistration.
Clinical parameters were compared preoperatively between patients with CPR-type diplopia and patients without diplopia and postoperatively between patients with persistent CPR-type diplopia and those with resolved diplopia and patients with new-onset diplopia and those who remained without diplopia. For non-normally distributed factors, nonparametric Wilcoxon rank sum tests were used. Mean values with a 95% CI around the mean difference were also calculated. Statistical significance was defined as P < .05.
Results
Patients
Thirty-three patients were identified; the median age was 67 years (range, 51-87 years). Eighteen of 33 (55%) were men and 32 (97%) reported their race/ethnicity as white. Ten of 33 (30%) were described in a previous study,4 but preoperative and postoperative data were not previously reported. Preoperatively, 12 (36%) had confirmed CPR-type diplopia and 21 (64%) did not have diplopia (Table 1). Fifteen of 33 (45%) had bilateral ERM (6 with diplopia preoperatively, 9 without diplopia).
Table 1. Clinical, Demographic, and Health-Related Quality-of-Life Factors in Patients With and Without Diplopia Before Undergoing ERM Peel Surgery.
| Factorsa | CPR-Type Diplopia Prepeel (n = 12) |
No Diplopia Prepeel (n = 21) |
P Value for Difference | Difference, % (95% CI) | Mean Difference (95% CI) | ||
|---|---|---|---|---|---|---|---|
| No./Total No. (%) | Mean (Range) | No./Total No. (%) | Mean (Range) | ||||
| Mean age, y | 12 | 66.8 (51-83) | 21 | 69.9 (56-87) | .31 | NA | −3.1 (−9.2 to 2.9) |
| Male | 6/12 (50) | NA | 12/21 (57) | NA | .73 | −7.1 (−42.5 to 28.2) | NA |
| Right eye peeled | 5/12 (42) | NA | 9/21 (43) | NA | >.99 | −1.2 (−36.2 to 33.8) | NA |
| Bilateral ERM | 6/12 (50) | NA | 9/21 (43) | NA | .73 | 7.1 (−28.2 to 42.5) | NA |
| ERM + ILM peeled | 9/12 (75) | NA | 20/21 (95) | NA | .13 | −20.2 (−46.4 to 5.9) | NA |
| Visual acuity operated eye,b logMAR |
12 | 0.29 (20/40) (0.00 [20/20] to 0.50 [20/63]) |
21 | 0.47 (20/63) (0.20 [20/32] to 1.00 [20/200]) |
.05 | NA | −0.18 (−0.33 to −0.03) |
| Interocular visual acuity difference (absolute) | 12 | 0.28 (0-0.50) | 21 | 0.39 (0-1.00) | .27 | NA | −0.11 (−0.27 to 0.05) |
| Optotype-frame test result positive | 8/11 (73) | NA | 4/19 (21) | NA | .009 | 51.7 (19.6-83.7) | NA |
| Synoptophore 5° positive | 5/8 (63) | NA | 6/14 (43) | NA | .66 | 19.6 (−22.8 to 62.0) | NA |
| Synoptophore 10° positive | 7/7 (100) | NA | 12/14 (86) | NA | .53 | 14.3 (−4.0 to 32.6) | NA |
| New aniseikonia test, % | 12 | 6 (−8 to 12) | 20 | 5 (0-12) | .37 | NA | 1 (−3 to 4) |
| AS-20 self-perception | 11 | 81.6 (25.8-100.0) | 20 | 95.8 (55.0-100.0) | .03 | NA | −14.2 (−26.9 to −1.6) |
| AS-20 interactions | 11 | 87.4 (59.5-100.0) | 20 | 96.9 (69.3-100.0) | .01 | NA | −9.5 (−17.2 to −1.8) |
| AS-20 reading function | 12 | 45.0 (6.7-74.6) | 20 | 68.7 (27.5-100.0) | .02 | NA | −23.7 (−40.4 to −7.0) |
| AS-20 general function | 12 | 43.6 (8.7-68.2) | 20 | 76.6 (17.5-100.0) | <.001 | NA | −33.1 (−48.4 to −17.8) |
Abbreviations: AS-20, Adult Strabismus-20 health-related quality-of-life questionnaire; CPR-type, central-peripheral rivalry-type; ERM, epiretinal membrane; ILM, internal limiting membrane; NA, not applicable.
No metamorphopsia data were reported because only 1 patient with diplopia had preoperative measurements.
Snellen equivalents shown in parentheses (nearest approximate Snellen value).
Preoperative Characteristics
Preoperatively, the mean visual acuity in the operated eye was better for the 12 patients (36%) with CPR-type diplopia than for the 21 patients (64%) with no diplopia (Table 1). Adult Strabismus-20 data showed lower scores (worse health-related quality of life [HRQOL]) in patients with diplopia compared with patients without diplopia (Table 1).
Postoperative Examinations
Six-month postoperative examinations were conducted at a median of 47 weeks (range, 18-138 weeks) for patients with preoperative CPR-type diplopia and 24 weeks (range, 9-82 weeks) for patients with no diplopia preoperatively. Thirty of 33 patients (91%) had undergone cataract surgery in the eye that underwent ERM peel at the outcome assessment (the remaining 3 [9%] had a visual acuity of 20/40 or better in the eye that had undergone ERM peel).
Resolution of CPR-Type Diplopia Postoperatively
Of the 12 patients with CPR-type diplopia preoperatively, 4 (33%; 95% CI, 10%-65%) had resolution of diplopia postoperatively (Table 2). Clinical, demographic, and HRQOL characteristics were similar between patients with resolved diplopia (4 of 12 [33%]) and those whose diplopia remained (8 of 12 [67%]), but postoperative AS-20 reading function scores were lower (worse HRQOL) for patients whose diplopia remained than for those whose diplopia resolved (Table 2).
Table 2. Clinical, Demographic, and Health-Related Quality-of-Life Factors in Patients With ERM and CPR-Type Diplopia Prepeel.
| Factorsa | Diplopia Remained Postpeel (n = 8 of 12 [67%]) |
Diplopia Resolved Postpeel (n = 4 of 12 [33%]) |
P Value for Difference | Difference, % (95% CI) | Mean Difference (95% CI) | ||
|---|---|---|---|---|---|---|---|
| No./Total No. (%) | Mean (Range) | No./Total No. (%) | Mean (Range) | ||||
| Mean age, y | 8 | 68.1 (59-83) | 4 | 64.0 (51-75) | .55 | NA | 4.1 (−8.3 to 16.5) |
| Male | 2/8 (25) | NA | 4/4 (100) | NA | .06 | −75 (−100 to −45) | NA |
| Right eye peeled | 5/8 (63) | NA | 0/4 (0) | NA | .08 | 63 (29-96) | NA |
| Bilateral ERM | 4/8 (50) | NA | 2/4 (50) | NA | >.99 | 0 (−60 to 60) | NA |
| ERM + ILM peeled | 6/8 (75) | NA | 3/4 (75) | NA | >.99 | 0 (−52 to 52) | NA |
| Preoperative Factors | |||||||
| Visual acuity operated eye,b logMAR |
8 | 0.30 (20/40) (0.10 [20/25] to 0.50 [20/63]) |
4 | 0.28 (20/40) (0.00 [20/20] to 0.50 [20/63]) |
.86 | NA | 0.03 (−0.21 to 0.26) |
| Interocular visual acuity difference (absolute) | 8 | 0.28 (0.10 to 0.40) | 4 | 0.28 (0.00 to 0.50) | .93 | NA | 0.00 (−0.23 to 0.23) |
| New aniseikonia test, % | 8 | 5 (−8 to 11) | 4 | 7 (0 to 12) | .61 | NA | −2 (−11 to 6) |
| Postoperative Factors | |||||||
| Visual acuity of operated eye | 8 | 0.20 (0-0.40) | 4 | 0.23 (0-0.40) | .93 | NA | −0.03 (−0.26 to 0.21) |
| Interocular visual acuity difference (absolute) | 8 | 0.16 (0-0.40) | 4 | 0.30 (0.10-0.40) | .19 | NA | −0.14 (−0.35 to 0.07) |
| New aniseikonia test, % | 7 | 5 (0-6) | 3 | 7 (5 to 11) | .46 | NA | −2 (−6 to 1) |
| Change in visual acuity in operated eyec | 8 | −0.10 (−0.40 to 0.00) | 4 | −0.05 (−0.1 to 0.0) | .33 | NA | −0.05 (−0.21 to 0.11) |
| AS-20 self-perception | 7 | 82.6 (0-100.0) | 4 | 92.4 (69.5-100.0) | .54 | NA | −9.7 (−54.0 to 34.5) |
| AS-20 interactions | 7 | 91.3 (69.8-100.0) | 4 | 91.0 (74.2-100.0) | >.99 | NA | 0.3 (−16.8 to 17.3) |
| AS-20 reading function | 7 | 45.0 (6.6-84.4) | 4 | 75.5 (64.3-95.1) | .05 | NA | −30.5 (−65.4 to 4.4) |
| AS-20 general function | 7 | 58.1 (8.7-84.1) | 4 | 80.0 (59.6-92.1) | .15 | NA | −21.9 (−59.8 to 16.0) |
Abbreviations: AS-20, Adult Strabismus-20 health-related quality-of-life questionnaire; CPR-type, central-peripheral rivalry-type; ERM, epiretinal membrane; ILM, internal limiting membrane; NA, not applicable.
Metamorphopsia values not summarized because there were limited data.
Snellen equivalents shown in parentheses (nearest approximate Snellen value).
Negative value signifies an improvement in visual acuity.
New-Onset CPR-Type Diplopia Postoperatively
Of the 21 patients with no diplopia preoperatively (64%), 4 (19%; 95% CI, 5%-42%) had new-onset CPR-type diplopia postoperatively (Table 3). The clinical, demographic, and HRQOL characteristics of patients with new-onset CPR-type diplopia (4 of 21 [19%]) and those who continued to have no diplopia (17 of 21 [81%]) are shown in Table 3. Despite similar preoperative visual acuity, mean (SD) postoperative operated-eye visual acuity appeared better (0.08 [0.10] logMAR vs 0.34 [0.33] logMAR; P = .07; Table 3) and mean (SD) postoperative aniseikonia appeared greater (14% [5%] vs 6% [4%]; P = .04; Table 3) for patients with new-onset diplopia than for those who never developed diplopia. Other clinical and demographic parameters appeared similar.
Table 3. Clinical, Demographic, and Health-Related Quality-of-Life Factors in Patients With ERM and No Diplopia Prepeel.
| Factorsa | New-Onset Diplopia Postpeel (n = 4/21, 19%) |
Remained Without Diplopia Postpeel (n = 17/21, 81%) |
P Value for Difference | Difference, % (95% CI) | Mean Difference (95% CI) | ||
|---|---|---|---|---|---|---|---|
| No./Total No. (%) | Mean (Range) | No./Total No. (%) | Mean (Range) | ||||
| Mean age, y | 4 | 71 (66-77) | 17 | 70 (56-87) | .75 | NA | −1 (−10 to 8) years |
| Male | 2/4 (50) | NA | 10/17 (59) | NA | >.99 | −9 (−63 to 46) | NA |
| Right eye peeled | 3/4 (75) | NA | 6/17 (35) | NA | .27 | 40 (−8 to 88) | NA |
| Bilateral ERM | 1/4 (25) | NA | 8/17 (47) | NA | .60 | −22 (−71 to 27) | NA |
| ERM + ILM peeled | 4/4 (100) | NA | 16/17 (94) | NA | >.99 | 6 (−5 to 17) | NA |
| Preoperative Factors | |||||||
| Visual acuity operated eye | 4 | 0.38 (0.2 to 0.5) | 17 | 0.49 (0.20 to 1.00) | .43 | NA | −0.12 (−0.39 to 0.15) |
| Interocular visual acuity difference (absolute) | 4 | 0.35 (0.10-0.60) | 17 | 0.39 (0-1.00) | .96 | NA | −0.04 (−0.32 to 0.24) |
| New aniseikonia test, % | 4 | 8 (6-12) | 16 | 4 (0-12) | .07 | NA | 3 (−1 to 7) |
| Postoperative Factors | |||||||
| Visual acuity operated eye,b logMAR |
4 | 0.08 (20/25) (0.00 [20/20] to 0.20 [20/32]) |
17 | 0.34 (20/40) (−0.10 [20/16] to 1.30 [20/400]) |
.07 | NA | −0.27 (−0.62 to 0.09) |
| Interocular visual acuity difference (absolute) | 4 | 0.10 (0-0.20) | 17 | 0.27 (0-0.90) | .19 | NA | −0.17 (−0.44 to 0.10) |
| New aniseikonia test, % | 4 | 14 (8-19) | 12 | 6 (0-12) | .04 | NA | 8 (2-13) |
| Change in visual acuity in eye that underwent ERM peel c | 4 | −0.3 (−0.4 to −0.2) | 17 | −0.15 (−0.5 to 0.5) | .16 | NA | −0.15 (−0.39 to 0.10) |
| AS-20 self-perception | 4 | 94.8 (79.2-100.0) | 16 | 96.3 (49.2-100.0) | .79 | NA | −1.5 (−16.0 to 13.0) |
| AS-20 interactions | 4 | 93.6 (74.2-100.0) | 16 | 97.1 (54.20-100.0) | .36 | NA | −3.6 (−17.4 to 10.2) |
| AS-20 reading function | 4 | 71.5 (47.7-95.1) | 16 | 78.5 (20.9-95.1) | .42 | NA | −7.0 (−27.9 to 13.9) |
| AS-20 general function | 4 | 79.9 (67.8-100.0) | 16 | 79.9 (17.5-100.0) | .29 | NA | −4.0 (−25.3 to 17.3) |
Abbreviations: AS-20, Adult Strabismus-20 health-related quality-of-life questionnaire; CPR-type, central-peripheral rivalry-type; ERM, epiretinal membrane; ILM, internal limiting membrane; NA, not applicable.
Metamorphopsia values were not summarized because there were limited data.
Snellen equivalents shown in parentheses (nearest approximate Snellen value).
Negative value signifies an improvement in visual acuity.
Discussion
Most patients with ERM do not have diplopia before undergoing ERM peeling, but the present study suggests that some of these patients will experience new-onset diplopia postoperatively. Conversely, some patients with preoperative diplopia will experience resolution after ERM peeling.
It has been previously reported2,4,9,10 that diplopia may emerge following ERM peeling. The present study confirms these previously reported findings and supports explaining the risk of postoperative diplopia to patients undergoing ERM peeling.9 It is currently unclear which factors precipitate the development of new-onset CPR-type diplopia following ERM surgery. Others2,10 have suggested an association with improved visual acuity, which is consistent with the findings in the present study (Table 3). Nevertheless, many patients showed improved visual acuity but did not develop diplopia. We speculate that diplopia develops when visual acuity improves but residual retinal abnormalities prevent simultaneous central and peripheral fusion. Further research is needed to elucidate specific factors that are associated with new-onset diplopia following ERM peeling.
The possibility of CPR-type diplopia resolving following ERM surgery has been suggested previously,2,11and Foroozan and Arnold12 reported a single case of resolved diplopia following ERM surgery. In the present study, 33% of patients had confirmed resolution of diplopia postoperatively. The reasons for improvement are unclear; a more detailed evaluation of retinal changes and other clinical parameters is needed in additional patients.
We found significantly lower (worse) AS-20 scores in patients with diplopia preoperatively (Table 1) compared with patients without diplopia and lower reading function scores postoperatively in patients whose diplopia remained vs those with resolved diplopia (Table 2). Further studies are needed to evaluate the relative magnitude of associations of specific visual symptoms, including diplopia, with reduced HRQOL.
Limitations
There are some limitations to our study. The small sample size resulted in wide confidence intervals for our estimates, but we believe it is important to highlight that new-onset and resolved diplopia do occur. Further research in larger populations would be helpful and may improve generalizability to other populations with ERM. In addition, the presence of bilateral ERM may have confounded our results, but only 15 patients were bilaterally affected.
Conclusions
Our data suggest that patients with ERM who previously did not have diplopia are at risk of developing CPR-type diplopia following ERM peeling and some patients who previously had diplopia may experience resolution of diplopia. These data may be helpful in counseling patients who are undergoing ERM peeling.
References
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